[ RadSafe ] TFP comment I, Sr Radiochemistry

Wed Jul 4 09:07:55 CDT 2007

Dear Erik,

Thank you for the link, which I had lost.

This is in the current discussion part I of my comments. In order to prevent
further speculations on that topic I put forward my "credentials" in this
case: I know the instrument used extremely well. I have given some ideas on
my perception of an ideal LSC counter in the early 80's, I have tested the
first prototype and I purchased the first (heavily discounted) sold
instrument. I have together bought five counters, finally in 1999 I had five
counters running day and night also during holidays and weekends. They were
used for radionuclide determination in environmental samples, including
tritium in precipitation and drinking water, Ra-226 and Rn-222 in water,
Rn-222 in air, C-14 and tritium in alcohol and vinegar, Sr-90 in food and
bioindicators and whatever else was to be solved by LSC. I might be regarded
as an expert on this instrument.

The information given on the link about the Quantulus is wrong. This
instrument is still manufactured at what was the Wallac Oy company in Turku,
Finland. Unfortunately Perkin Elmar discontinued the production of excellent
other LS-counters at Turku after the purchase. Does that mean, that those
people do not even know, where their instruments are manufactured? 
-------------------------------------------

To your concerns:

Ad 1) The Quantulus is equipped with an alpha-beta separation capability. In
case radium would be present in the measurement sample it could be easily
detected and corrected for. I have no hint, that it was accounted for, but
not any hint either that it was  n o t  acounted for.

Ad 2) I agree that there is no information about the quench. Since Sr-90 and
Y-90 have relative high beta energies the quench might not be to serious -
but this should be checked.

Ad 3) I agree totally with regard to the statistics, but I doubt that the
influence of different sample composition of the background samples on the
results would be very significant.

Ad 5) The "intercomparisons" mentioned are nothing but a bad joke!!! The
laboratory mentioned is obviously not accredited - how could it be, when
just comparing one or two samples with another not accredited laboratory?

Nevertheless, these arguments do not necessarily contradict the observed
variations of Sr-90 concentration in teeth. 

Wait for my TFP comment II for more information!

Best regards,

Franz

Franz Schoenhofer, PhD
MinRat i.R.
Habicherg. 31/7
A-1160 Wien/Vienna
AUSTRIA

-----Ursprüngliche Nachricht-----
Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im Auftrag
von Nielsen, Erik
Gesendet: Dienstag, 03. Juli 2007 20:38
An: radsafe at radlab.nl
Betreff: [ RadSafe ] Mango's Tooth Fairy Sr Radiochemistry

Mango has documented the methods used for his NJ Toothfairy project.  It
can be found at:
http://unplugsalem.org/radioactive_strontium.htm

As a radiochemist I have a number of concerns about the analytical
methodology.

1. The seperation technique is not elementally specific and is not
generally accepted as accurate.  Specifically there is no seperation
chemistry to remove radium.  This could result in a high bias based on
naturally occurring Ra-226 and Ra-228 codeposited with calcium.  New
Jersey is known to have Ra-226/228 and Ra-224 issues in their drinking
water.  The seperation chemistry is so non specific that they purport to
precipitate yttrium with the calcium and strontium.

2. Liquid scintillation efficiencies are affected by chemical and color
quenching.  The method is unclear on quench corrrections. The efficiency
was calculated using standards in a different acid composition than the
samples.

3.  Statistical errors made in calculating detection limits based on
backgrounds counting significantly longer than sample counting times.
Unclear if backgrounds are the same acid compostion as the samples.

4. No yield correction attempted for recovery fraction of the stable
carriers added.

5. Nothing other than self referential material found on google for
Radiological and Environmental Measurement Systems of Waterloo, Candada.
It's only customers seem to be anti-nuclear activist organizations:
Military Toxics Project, National Gulf War Resource Center and the Tooth
Fairy Project. 

Erik C. Nielsen 
Senior Scientist 
Remote Sensing Laboratory 
P.O. Box 98521, M/S RSL-47 
Las Vegas, NV 89193-8521 

http://www.nv.doe.gov/nationalsecurity/homelandsecurity/frmac/default.ht
m 

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